write-only memory

write-only memory n.  The obvious antonym to `read-only
   memory'.  Out of frustration with the long and seemingly useless
   chain of approvals required of component specifications, during
   which no actual checking seemed to occur, an engineer at Signetics
   once created a specification for a write-only memory and included
   it with a bunch of other specifications to be approved.  This
   inclusion came to the attention of Signetics {management} only
   when regular customers started calling and asking for pricing
   information.  Signetics published a corrected edition of the data
   book and requested the return of the `erroneous' ones.  Later,
   around 1974, Signetics bought a double-page spread in
   "Electronics" magazine's April issue and used the spec as an
   April Fools' Day joke.  Instead of the more conventional
   characteristic curves, the 25120 "fully encoded, 9046 x N, Random
   Access, write-only-memory" data sheet included diagrams of "bit
   capacity vs. Temp.", "Iff vs. Vff", "Number of pins remaining
   vs. number of socket insertions", and "AQL vs. selling
   price".  The 25120 required a 6.3 VAC VFF supply, a +10V VCC, and
   VDD of 0V, +/- 2%.